Sources and Concentration of Chloroform Emissions in the South Coast Air Basin. Final Report

摘要

The objectives of the study were to identify and quantify sources of chloroform emissions in the South Coast Air Basin, and to relate emissions to ambient concentrations. Phase I consisted of a literature review; written and telephone surveys of users of chloroform precursors (water and wastewater treatment plants, cooling tower users, pulp and paper plants, pharmaceutical manufacturers, laboratories, and hospitals); and modeling to relate estimated emissions to historically observed concentrations. A machine-readable annotated bibliography was also developed. Phase II included ambient sampling by carbon molecular sieve at sites throughout the Basin and at two fixed sites; source testing of a swimming pool (using a surface isolation flux chamber) and at two wastewater treatment plants; sampling of marine air and water; and smog chamber modeling of hypothesized atmospheric formation and removal processes. New emissions estimates were developed from field measurement data and the resulting modeled concentrations fit the observed values reasonably well. A conceptual model of cycling of chloroform between the ocean and the atmosphere over the Basin was proposed.